In a known apparatus of this kind, the brushes are so suspended that in the basic position of the brushes their axes of rotation are vertical. In the basic position, the two brushes are brought as close to one another as possible and are located in the vicinity of the longitudinal axis of the vehicle. Both in conveyor belt washing systems and in gantry washing systems the vehicle carries out a continuous relative movement with respect to the brushes during the washing operation. In conveyor belt systems, the vehicle is drawn through the brushes which are mounted in a stationary frame, while in gantry washing systems the vehicle is stationary and the gantry bearing the brush is moved. In both cases the front surface of the vehicle strikes first against the rotating brushes. Since the vehicle moves on continuously, the contact pressure of the brushes against the front surface is intensified. The intensified contact pressure is utilized to move the two brushes in opposite directions out of their basic position into a lateral position by means of suitable servomotors along a path extending transversely of the longitudinal axis of the vehicle. In the process the brushes wash the front surface of the vehicle. Since, however, the vehicle also moves on while the brushes move outwardly, the brush is carried along by the vehicle at its lower end and is swung out about its pivot axis. When this happens, however, the swinging-out must take place only within a limited small angle, since otherwise the front surface of the vehicle is only washed in its uppermost zone and the contact pressure of the brushes moreover becomes too strong and damage to the vehicle is to be feared. For this reason, in known washing equipment, the brushes must be moved apart comparatively rapidly during the washing of the front surface, whereby the washing effect suffers.
The problem underlying the invention is to provide a vehicle washing apparatus of the kind mentioned at the beginning which in particular makes better cleaning of the front surface of the vehicle possible and also a higher rate of advance of the vehicle.
According to the invention, this is achieved in that in the basic position of the brushes their axes of rotation are inclined at an acute angle with respect to the vertical and in fact with their upper ends in the direction of relative movement of the vehicle.
Thus, in the new apparatus, the brushes no not hang vertically in their basic position, but their axes of rotation are so inclined obliquely with respect to the front surface of the vehicle that the lower end of the brush is closer to the vehicle than the upper end. When the vehicle strikes against the brush, it is first swung out of its inclined position into its vertical position and finally into an oppositely directed inclined position during the forward movement of the vehicle. Consequently, a double angle of swing is available until the brush has reached its position of greatest possible inclination during the forward movement of the vehicle. Owing to the doubling of the angle of swing, it is possible to move the brushes apart at a lower speed during the washing of the front surface. This results in a better washing effect. Moreover, it would also be possible to retain the existing speed with which the brushes are moved apart and double the rate of advance of the vehicle instead. The optimum solution would probably be one in which, compared with known washing equipment, both the speed with which the brushes are moved apart is reduced a little and the rate of advance of the vehicle is increased. Irrespective thereof, howevere, a better washing effect is moreover also achieved in the lower zone of the front surface of the vehicle.
With each brush there is advantageously associated a second brush arranged behind it in the direction of movement of the vehicle and the two brushes of a pair of brushes formed in this way are suspended to swing about a common pivot axis, the axes of rotation of the brushes of a pair of brushes moreover having their upper ends inclined towards one another. With this construction, a particularly good washing effect is obtained at all the surfaces of the vehicle. The brushes arranged in the first position in the direction of movement of the vehicle wash the front surface, then both brushes wash the side surface and finally the second brushes wash the rear surface of the vehicle.